This application describes an improvement over the disclosure of Patents Nos. 5,583,324 and 5,691,516, an improvement whereby a vibration absorber according to the invention of any of those applications is tunable to a select broad band of continuously varying frequencies upon installation into a speaker cabinet or other speaker enclosure.
In this invention the stack of viscoelastic damping plates, secured together with spacers preferably at one edge, is connected to the speaker panel with an angular shaped tuning mounting plate between the damping unit's base or mounting plate and the speaker panel. As in U.S. Pat. Nos. 5,583,324 and 5,691,516, the stack of plates is secured together and to the unit's mounting plate at one edge, with spacers between plates at the bound edge. Upon installation on the panel of a speaker enclosure, the edge of the unit where all plates are secured together is cantilevered over the edge of the angular shaped tuning mounting plate. The degree of cantilever between the bound edge and the edge of the angular shaped mounting plate varies according to a selected shape and angle such that the unit may be tuned to a select broad band of continuously varying frequencies. The vibration absorbing unit is then fixed to the angular-shaped mounting plate to absorb vibration over the selected broad band of continuously varying frequencies.
It is therefore among the objects of this invention to improve the vibration absorbing capability of vibration damping units such as described in U.S. Pat. Nos. 5,583,324, and 5,691,516 with a simple and efficient procedure. These and other objects, advantages and features of the invention will be apparent from the following description of a preferred embodiment, considered along with the accompanying drawings.